Patent FR-2907892-A1 (FR)
Title: Pyrotechnic gas generating device useful in automobile, comprises frame for maintaining integrity of device during its operation and ensuring regulation of release of generated gas, and ignition system partially inserted in primary chamber
Inventor: CORD PAUL PHILIPPE
IPC: B60R21/26
Filed: 2006-10-26
Abstract: The pyrotechnic gas generating device useful in an automobile, comprises a frame for maintaining integrity of the device during its operation and ensuring a regulation of release of generated gas, an ignition system partially inserted in a primary chamber (3), and an elongated cylinder. The frame defines a primary chamber for storing and burning a primary pyrotechnic compound (8), a secondary chamber (14) for storing and breaking down a secondary compound, and a stabilization zone (22) having a wall. The primary chamber comprises expelling nozzles. The pyrotechnic gas generating device useful in an automobile, comprises a frame for maintaining integrity of the device during its operation and ensuring a regulation of release of generated gas, an ignition system partially inserted in a primary chamber (3), and an elongated cylinder. The frame defines a primary chamber for storing and burning a primary pyrotechnic compound (8), a secondary chamber (14) for storing and breaking down a secondary compound, and a stabilization zone (22) having a wall. The primary chamber comprises expelling nozzles, and secondary chamber comprises an inlet opening (20) and a wall, which produces an interface of the secondary chamber and the outside of the gas generator. The primary and secondary compounds form an explosive charge (10 grams) of the gas generator. The stabilization zone communicates with the secondary chamber through an evacuation opening and with outside of the gas generator through a hole of an exhaust pipe. The ignition system comprises a unit for receiving an electrical charge, and is adapted for initiating the combustion of the primary compound. The wall of the secondary chamber is made of gas-tight solid polymeric material, which is used for forming a lighter wall having a mechanical-property decay temperature lower than 300[deg] C and having mechanical characteristics such that the secondary chamber has an inner volume during operation lower than four times the inner volume under rest conditions. The device is operated at higher than 15 ms. The stabilization zone extends between the primary and the secondary chambers. The secondary chamber extends between the primary chamber and the stabilization zone, where the primary chamber directly communicates with the secondary chamber through an intermediary of expelling nozzles and inlet opening. The secondary compound is formed of pellet and granule. The wall of the stabilization zone produces an interface between an inside of the stabilization zone and the outside of the gas generator. The hole of an exhaust pipe is fixed in the stabilization zone wall, which is made of gas-tight solid polymeric material for forming a lighter wall having a mechanical-property decay temperature lower than 120[deg] C and having mechanical characteristics such that the stabilization zone has an inner volume during operation lower than four times the inner volume under rest conditions. The wall of the secondary chamber and the stabilization zone has a maximum thickness of 1-3 mm. The primary chamber, the stabilization zone and the secondary chamber are placed in the elongated cylinder according to an axial direction of the gas generator. A periphery of the secondary chamber wall and the stabilization zone wall cylindrically extends on a total length of the secondary chamber and the stabilization zone respectively according to the axial direction of the gas generator. The periphery of the secondary chamber and the stabilization zone walls are formed by a same tube. A maximum external diameter of the elongated cylinder is = 25 mm. The secondary compound is stocked in the secondary chamber and conditioned in a flexible sealed bag or a rigid cartridge.